Method and system for treating ore



Jan. 14, J. P, MCCARTY ETAL METHOD AND SYSTEM FOR TREATING ORE Filed March 17. 1961 3 Sheets--Sheel l dameJ MC60/'fg C//a//su H. Ca//J INVENTUM AVER/460V@ EI//CE HAT/0 Jan. 14, 1964 p, MCCARTY ETAL 3,117,734

METHOD AND SYSTEM FOR TREATING ORE l Filed March 1'7, 1961 3 Shets-Sheet 2 Jan. 14, 1964 Filed March 17, 1961 J. P. MCCARTY ETAL METHOD AND SYSTEM FOR TREATING ORE 3 Sheets-Sheet 3 3,117,734 NETHOD AND SYSTEM FOR TREATING ORE James l. McCarty and Charles H. Curtis, Tucson, Ariz.,

assignors to Duval Sulphur 8l 'Potash Company, Houstou, Tex., a corporation of Texas Filed Mar. 17, 1961, Ser. No. 96,600 18 Claims. (Cl. 241-29) This invention relates to material processing methods and systems, and more particularly to control of crushing devices.

lAn object of this invention is to operate crushing devices, particularly of the cone type, at selected capacity, preferably optimum, without overloading.

Another object is lto operate crushing devices, particularly of the cone type, without subjecting them to an overload.

Another object is to 'operate crushing devices, particularly of the cone type, at selected efficiency by continuously introducing into the crusher the right amount of material needed to operate the crusher :at selected elliciency.

Another Iobject is to operate a crusher of the cone type at a selected efficiency by governing the height of the cone relative to the crushing ring in accordance with the loading of the crusher.

Another object is 'to operate a crusher, particularly of the cone type, at selected etliciency with fan automatic control system which will supply 'approximately the proper amount of feed to operate the device at selected efficiency.

Another object is to operate a crusher, particularly of 4the cone type, at maximum eficiency with an `automatic control system which will position the cone in relation to the ring to operate the device at maximum efliciency.

Another object is to automatically operate a plurality of the crushing devices arranged to crush material in sucessive stages at selected elliciency, and particularly to operate such devices automatically.

Another object is to provide an automatic control system and method of operation for crushing devices, particularly Iof the cone type, in which a primary crusher feeds material to -a plurality of secondary Crushers in which the secondary Crushers are automatically maintained under selected loading.

:Another object is to provide an automatic control system and method of operation for crushing devices, particularly of the `cone type, in which la prim-ary crusher feeds material to a plurality of secondary cru-shers in which the secondary Crushers are automatically maintained under selected relative :loading and additionally automatically controlling the amount of material fed to the primary crusher in response to the needs of the secondary crushers to :operate Ithe secondary crushers at selected eiliciency, and in which the primary crusher is maintained at selected operative eflici-ency by autom-atic-ally positioning the mantle with respect to the concave in accordance with the loading of the primary.

Another object is to provide an automatic control system and method of operation for crushing devices, particularly of the cone type, in which a primary crusher feeds material to a plurali-ty of secondary 'Crushers in which the secondary Crushers are :automatically maintained under selected relative loading and additionally automatically positioning the mantle with respect to the concave of the primary crusher in response to the needs of the secondary Crushers to operate the secondary crushers iat selected efficiency, and in which the primary crusher is maintained at selected operative efficiency by automatically controlling the amount of material fed to the primary crusher in accordance with the loading of the primary crusher.

l i173@ Patented Jan. 14, 1964 Another object is to provide an over-riding control and method of operation of the plurality of crushing devices as in the preceding 4objects in which the over-riding control on any of the crushing `devices over-rides all of the control system and effects a reduction in feed of material to the primary crusher when the level of material in any one of the Crushers is above :a selected level, or effects a change in size of material .to the overloaded crusher to relieve the overload condition.

Another object is to provide an automatic control system and method of operation for crushing devices, particularly of the cone type, in which a primary crusher feeds material to a plunality of secondar;r Crushers, and in which the secondary Crushers are automatically maintained under selective relative loading, and in which all of the ciushers are operated at a desired efficiency, preferably maximum efficiency.

Other objects, features and advantages of this invention will be apparent from the drawings, the specification and the claims.

This invention is characterized by the operation of a single crusher, or a plurality of Crushers in stages, at selected eliciencies. The desired operating efficiencies of lthe units are maintained through control of the volume of feed, by varying the speed of the feed conveyor, or through control of the size of the material in the feed, by varying the cone position and setting of the previous crusher stage, or through Icontrol :of the degree of crushing and size reduction by the crusher, by varying the cone position and setting of the crusher. rIllie operating efliciencies of the units are determined lby sensing their loading condition which is accomplished by sensing the power input to .the drive, lor by sensing the thrust on the cone (crushing pressure), or by sensing the level of the material in the crusher.

Where a single crusher is involved the operating efficiency or loading can be determined by sensing tlie power input, the thrust on #the cone, or the level of the material in the crusher, and the desired efficiency or crusher loading can be maintained by varying the feed rate to the crusher or by varying the lcone position relative to the ring of the crusher.

[Where crushers 'arranged in stages `are employed, the control system and method are more complex. Wliere a plurality of secondary crushers are employed the loading of each secondary is sensed and compared. A divider is placed in the stream `of material passing from the primary to the secondaries. This divider or proportioner is shifted in accordance with the 'compared loading to direct the right amount of material to each secondary to maintain the desired relative etlciency of operation yof the secondaries. The sensed loading on the secondaries is also utilized to control the overall etliciency of the second-aries. This sensed loading may be utilized to control either the overall feed to the entire system or the size of material discharging from the primary crusher. For instance, the secondary loading may control the speed of the conveyor delivering material to the primary crusher. In this case it is preferred to 'also sense the loading on the primary crusher and change the cone position to also maintain the primary crusher operating :at a selected efficiency. As an alternative, it is possible to have the loading on the secondaries control the Icone position of the primary crusher. In this arrangement the loading fon the primary is sensed and the speed of delivery of material to the primary is controlled in accordance with the loading on the primary.

In the drawings, wherein like reference numerals indicate like part-s, and wherein illustrative embodiments of this invention are shown:

FIGURE l is a schematic illustration of the method of operating a crusher;

FIGURE 2 is a schematic illustration of the method of operating a plurality of Crushers;

FIGURE 3 is a schematic illustration yof the method of oper-ating a plurality of Crushers in which all Crushers may be operated yat a desired emciency; and,

FIGURE 4 is a view similar to FIGURE 3 in which the load on the crushers is sensed by determining the level of material therein.

In the single Crusher form of this in fention, the rate of delivery of material to the Crusher or degree of crushing is controlled according to the efficiency at which the Crusher iis operated. Thus, desirably, if the Crusher is operating below efficiency, more material is fed to the ciusher or it isset to crush to a smaller size so that it may operate at maximum efficiency. lf too much material is being .ffed to the `Crusher and it is being overloaded, then the feed of material to the Crusher is reduced to permit it `to regain optimum operating conditions. Ariternatively, the finished size may be increased. In accordance with this invention, the loading of the Crusher is utilized as the control medium, and the power consumption, level of material in the Crusher, or hydraulic pressure of the Crusher is utilized as indicia of the eiiiciency at which the Crusher is operating.

Referring first to FIGURE l, the invention is shown in `a system wh-ich includes a cone-type Crusher indicated generally at 10. The crusher illustrated is sold by the Allis Chalmers Company, of Milwaukee, Wisconsin, under the trade name Hydrocone, and is lfully illustrated in Company Publication No. 07B7l45B. As indicated in FIGURE l, the cone crusher includes a Crusher ring 11 and a cone or mantle 12 which cooperates with the ring l1 to crush material fed into the mouth 1.3 of the Crusher. The cone 12 is mounted for gyration. The cone y12. has provided on its `spindle a gear 14 which meshes with a drive gear 15 on the arbor 16 of motor M. Operation of motor M causes gyration of the cone `12 which crushes the material between the cone and ring l1.

Material from the Crusher 16 is discharged onto the conveyor belt indicated generally at 17 which conveys the crushed material to the next treating stage in the operation.

Material is fed to the cone crusher by any desired feed means, such as 4the conveyor belt indicated generally at 18. This conveyor bel-t is designed for variable speed operation for purposes of control of Ithe crusher, as will more fully appear hereinafter. Material from the conveyor 18 is discharged onto the. screen indicated generally at 19, wherein material below a predetermined mesh size bypasses lthe Crusher 10 and is conveyed directly to the conveyor I17.

Any desired means may be used to sense the instantaneous power consumption of the Crusher, such as a thermo-converter sensing device or a contact-making ammeter, land the signal `from the sensing device utilized as the basis for control of lthe speed of the conveyor l, or the positioning of the cone 12.

Alternatively, the control system can utilize a pressure sensing device whereby the pressure on the hydraulic cone support syste-m serves as the indicator of the Crusher loading (see FIG. 3), or the level of material in the Crusher xmay be determined las in FIG. 4. In FIG. l a power sensing device 21 senses the load on the crusher by sensing the load on motor M. This sensing devi in combination with a controller 22 regulates the variable speed drive unit for the conveyor 13. The variable speed drive for conveyor 18 is schematically represented in the drawings at 23. As the details of construction and operation of the power-sensing device and the controller are not material, and any -desired type could be used, they are also schematically represented in the drawings.

With the system of FIGURE 1, a determination may be made of the maximum eiliciency to be obtained with the Crusher under given operating conditions, and the power consumption of the Crusher under these conditions determined. Then .the controller system 22 may be set so that when the signal generated by the powersensing device 2d is equal to this optimum value, no change is 'made in the speed of conveyor 18. However, when the power-sensing device indicates use of a lesser amount of power, then the controller should signal the variable speed unit 23 to increase the speed of conveyor 1li to lfeed more material in-to ythe crusher so that it will be operating under greater load conditions to bring it hack to maximum efficiency. In like manner, where the unit is overloaded land the power-sensing device is indicating use of an excess vamount of power, the controller system would signal the variable speed control of the conveyor to slow down the conveyor and reduce the flow of ma erial to the crusher. It will be understood that, alternatively, the position of lthe cone or crusher setting can be modified instead of the feed rate to maintain the desired yCrusher loading or eificiency. It will also be understood that as alternates to the power consumption, either the crushing pressure, or the level of the material in the Crusher can be utilized as indicators of the crusher loading.

If desired, la recorder might be included in the controller system to plot against time one or more of the signals flowing through the controller system to give a permanent record of operation of the Crusher.

To guard against overloading of the Crusher, a levelsensing device -i is provided which is `actuated lwhen the level of material in the Crusher rises above a desired point. The level-sensing device, upon being actuated, signals the `controller system 22 and the controller system is constructed so that the level-sensing device is an overriding control and over-rides the signal induced by the load-sensing device to call for a reduction in speed of the conveyor 1? until such time as the level-sensing device is deactivated.

Referring now to FIGURE 2, a system is shown for operating a plurality of crushers. A pair of secondary Crushers indicated generally at 1Gb and 16C receive material from the primary Crusher 19a and further crush the materi l. As in the FlGURE l for-m of the invention, the material is fed to a screen 19 by a means such as conveyor 18 whose speed is variable.

Material crushed by primary Crusher 1de is discharged onto the receiving means indicated generally at 2G. This means receives the material and divides it into separate portions `and conveys the separate portions to the secondary Crushers 1Gb and 16C.

in accorda-nce with this invention, the two crushers 165 and tc are operated at selected loads by dividing the material from tl e primary Crusher on the receiving means Ztl and feeding to the secondary Crushers approximately :the right amount to operate them at the selected loads. Preferably both secondary Crushers are operated at maximum eiiiciency. For this purpose the receiving means 2li is lautomatically controlled to divide and deliver to the secondary crnshers the right amount of material. Preferably the receiving means 2t? is a platform Z6 receiving material from primary crusher lila and positioned to overlie at each end the two secondary crushers. The platform 26 may be conlined by side walls (not shown) on two opposite sides to direct flow toward the two secondary cnushers.

lt will be noted that the receiving means Ztl receives material at its mid-section and extends yfrom the receiving section to points over the secondary Crushers. This causes material to pile up on platform 25 in a dividing ridge. With the platform 26 centered between the secondary Crushers, an equal amount of material is directed to each Crusher. By moving the platform 2d toward Crusher ltlb the dividing ridge is shifted with the platform 26 toward Crusher 1.65 and thus more material will be fed into Crusher 19C than crusher leb. If a more positive split is desired, an artificial dividing ridge might be provided by an upright member carried on the center section of platform 26. It will of course be apparent that more than two secondary crushers might be utilized and that the material from the primary stage of crushing might be divided in any desired Way. The illustrated embodiment is preferred because it does not employ parts readily eroded by contact with the stream of material. Preferably the platform 26 may be shifted along a line extending between the two secondary Crushers ltlb and c automatically in accordance with the relative loads between the secondary Crushers.

In maintaining the relative loading on the secondary Crushers at selected values, their loads are sensed and compared, and a control system utilized to shift the position of platform 26 in accordance with the comparison. In carrying out this control system, a power-sensing device 2S senses the load on secondary Crusher 10b and a similar power-sensing device 2? senses the load on secondary Crusher 10c. The signals from these sensing devices are then fed into a splitter control 32 which compares the output of the power-sensing devices 23 and 29, and, if the signals indicate that the secondary Crushers are not operating at the desired relative loads, the splitter control operates the shift control positioner 34 to shift platform 26 on supports 30 in the proper direction to shift the proportion of the output of the primary Crusher to the secondary Crushers to cause them to operate at approximately the desired relative loads. Preferably, the secondary Crushers are operated at equal etiiciencies in this manner. In some instances it may be desired to operate the secondary Crushers at difference loads. For instance, where one Crusher has new crushing surfaces and the other Crusher has older crushing surfaces, it will be apparent that maximum eiciency will be obtained with different loads on the Crushers. Therefore, it is preferred to place a loading ratio device in the power-sensing circuit such as at 31. This device may suitably multiply or divide the signal from power-sensing device 28 to feed a false signal into splitter control 32. With loading ratio device set 'at other than a l to 1 ratio, 4the platform 26 will tend to remain in an olf-center position and load one Crusher more than the other crusher. In this manner each Crusher may be operated at the same eciency.

A signal is fed by each of the power-sensing devices of the secondary Crushers to controller recorder system 22 and the combined signal controls variable speed unit 23 in the manner previously explained to supply the right amount of material to operate the secondary Crushers at maximum efficiency. Preferably, the power-sensing devices signal an averaging device 33 which averages the power-sensing device signals and feeds the average signal to the controller-recorder system 22. System 22, the variable speed means 23 and the conveyor belt 18 are identical with those shown in FIGURE l, and the signal from the averaging device operates the controller system to increase or decrease the amount of material fed to the primary Crusher, which in turn will increase or decrease the amount of material passing to the secondary Crushers and maintain the amount of feed through the system at a value which will give maximum eliiciency of operation of the secondary Crushers. It Will be understood that the loading of the secondary Crushers can be determined not only by sensing the power consumption, as just described, but alternatively by sensing the crushing pressures, or by sensing the level of material in the Crushers.

As in the FIGURE l embodiment, each of the crushers is provided with a level-sensing device 24 which when activated signals the controller system to reduce the amount of material fed to the system until such time as the overloaded Crusher is relieved.

While only a pair of secondary Crushers is shown, it is apparent that, if desired, a larger number of Crushers could be used and a suitable dividing means provided for dividing the material among the several crushers in the manner taught herein.

It is apparent that the rate of material fed in a twostage system may be controlled as in FIGURE l, and the material distribution controlled as in FIGURE 2, but the entire system of FIGURE 2 is preferred.

Reference is now made to FIGURE 3 which illustrates the preferred form of the invention when multiple crushers are used. In this form of the invention the etiiciency of operation of all of the Crushers may be controlled.

A primary Crusher 10d receives material from conveyor belt 18 over screen i9 and delivers material to platform 26.

In order to operate the primary crusher 10d at desired efciency, means are provided :for adjusting the position of cone I2 relative to ring 11 to thus operate the primary Crusher 10d at desired efficiency. Preferably this will be maximum efliciency. To provide for adjustment of cone 12, it is mounted on :a plunger 3S which is vertically reciprocal within cylinder 36. Hydraulic Huid under pressure is supplied to the cylinder 36 through conduit 37. The hydraulic fluid in cylinder 36 is transferred to or from the cylinder from reservoir 38 in accordance with the needs of the system.

The amount or hydraulic fluid in cylinder 36 will determine the height of cone l2 relative to ring l1, and this amount may be supplied or removed in any desired manner in response to the needs of the system to maintain the primary crusher 10d under the desired load conditions. For instance, the load on the primary Crusher might be determined in the manner disclosed in FIGURE l, or the pressure under which the fluid is confined in cylinder 36 may be determined by a pressure sensitive device 39. The pressure Within chamber 36 will be a measure of the load on the primary Crusher ld. A signal representative of the load on the primary Crusher is transmitted to `a pressure sensitive controller 41 which will signal the release or addition of hydraulic fluid from or to chamber 36 as needed to keep the Crusher operating at the desired level of eiiiciency. The pressure sensitive controller 41 might be provided by any device having a variable set point and capable of generating or controlling a signal when the input signal to the controller is above or below the predetermined set point by a selected amount.

The reservoir 38 is connected to conduit 37 through parallel conduits 37al and 37b. A pump 42 is provided in branch conduit 37b and is maintained in constant operation by a motor 43. The pump is of the type having a built-in bypass and maintains the conduit 37b under a selected pressure.

Flow of additional fluid to cylinder 36 is provided by the pressure sensitive controller 41 opening a solenoidcontrolled valve indicated generally at 44. When this valve is opened, the output from pump 42 is fed through lines 37b and 37 into chamber 36 to raise cone 12 and increase the load on the cone Crusher. As soon as the pressure on the Huid in chamber 36 comes up to the selected value, the pressure-sensitive controller 41 will close valve 44 to retain this pressure on the fluid in cylinder 36.

In the event the Crusher 10d becomes overloaded, the pressure Within cylinder 36 will be excessive which will be signalled to the controller 41. The controller 41 will in turn open fluid controlled valve indicated generally at 45 in branch line 37a to permit flow of hydraulic fluid from cylinder 36 through conduits 37 and 37a into the reservoir 38.

In the event of a sudden overload of the Crusher 10d, pressure Within cylinder 36 will be relieved by device 46. This device is conventionally used for this purpose and is a closed chamber having a gas filled bladder therein which can be collapsed under excess pressure to permit ow of hydraulic iluid from cylinder 36. The pressure at which the bladder relief means 46 will collapse is greater than the operating range of pressure which is controlled by controller 41. Thus, the relief means 46 will not interfere with normal operation of the system to maintain the primary Crusher operating at desired ethciency, but in the event of a sudden overload will relieve pressure within cylinder 36 to protect the primary crusher.

The pressure gauge 47 indicates the pressure within cylinder 36. To illustrate a different manner of control with overload means 24 it has been connected to controller 4.1i and will override signals from sensing means 39 to relieve pressure in cylinder 36 in case of material building up in the Crusher high enough to energize the overheight control means 24. Obviously, the primary Crusher shown and controlled as in FlG. 3 might be used alone or in conjunction with the secondary Crushers. It is further obvious that controller 4l might control the speed of conveyor i8. In like manner, controller 22 of FIG. l might control the height of piston 35.

Material from the primary Crusher 16d is delivered to platform 26, which in turn transfers the material to the two secondary Crushers ltlb and ille. These Crushers and their control systems are identical with the system shown in FIGURE 2.

It might be noted that in FIGURE 3 the means for handling the platform 26 is shown in slightly more detail. To shift the platform 26, a piston 4S carried by the platform reciprocates within a cylinder 49. Fluid lines 51 and 52 convey hydraulic lluid to and from the cylinder 49 on opposite sides of piston 4S. These two lines 5l and 52 connect to opposed outlets of a four-way valve indicated schematically at 53. The other two outlets of the four-way valve are connected to lines 54 and S5 which are in turn connected to reservoir 56. A continuously operating pump 57 is provided in line 55. Thus, with the four-way valve set for inter-connecting lines 54 and 55, iiuid merely circulates through the fourway valve. When the valve is shifted in one direction, it interconnects lines 51 and 57 and also interconnects lines 52 and 54 to introduce pressure fluid into cylinder 49 through line 5l and to remove fluid from the cylinder through line 52. When the four-way valve is shifted in the other direction, the reverse llow of iluid occurs. The operating handle for the four-way valve 53 is connected to two solenoid operators S and 59. Thus, when solenoid 5S is actuated the four-way valve is shifted in a direction to introduce pressure through line 51 into cylinder 49. When solenoid 59 is actuated, the four-way valve 53 is shifted to introduce pressure into cylinder 49 through line 52.

The two solenoids 5S and 59 are controlled by the splitter control. set to maintain the platform 26 at its median position with nine pounds of instrument air and the power-sensing device 28 sends an eight pound signal due to underloading of crusher b, while at the same time the powersensing device 29 is sending a nine pound signal, then splitter control 32 will compare these two signals and effect operation of solenoid 59 to open four-way valve 53 and shift the platform 26 toward Crusher lill; to increase its load. Of course, the reverse operation would occur if the loading on the two secondary Crushers be reversed.

It will be apparent that desirably the system for controlling the three crushers be so designed that there will not be a constant seeking of each of the control means due to minute changes in conditions. To avoid such conditions, preferably means are provided where needed in the system to permit a signalled change to be eliective through only a short period of time. For instance, the splitter control 32 would include a timer which would limit the duration of signals to solcnoids 58 and 59 and would limit the frequency in which a new signal might be generated in these circuits during a finite period of time. Gther portions of the system, such as the controller recorder system 22, might likewise lbe provided For instance, if the splitter control is with means for limiting the frequency and magnitude of changes of the variable speed unit 23.

In the operation of the system shown in FGURE 3, material from a suitable source will be delivered by a conduit 18 to screen l* which will direct the larger particles into primary Crusher 10d. This Crusher will coarsegrind the material and deliver it to the platform 26 which will in turn deliver it to the secondary Crushers tlb and ltlc. The material will be further crushed to a smaller size and then removed by suitable conveyor means for further treatment. The control system for platform 26 will maintain the two secondary Crushers operating at approximately the same efficiency, preferably maximum eliiciency.

The device 33 will sense the load of each of the secoudary Crushers and will generate a signal responsive to this load which will be sent to the controller recorder system 22. While the device 33 is an averaging device, it will be appreciated that any device for sensing the total load on the power-sensing devices 28 and 29 and generating a signal proportional to the sum, or some proportion of the sum, may be employed. In the event the device 33 is signalling a need for additional material to maintain the secondary crushers operating at maximum eiciency, the controller system will increase the speed of the conveyor l?) to produce such material. rThis might perhaps increase the load on primary Crusher tltl to slightly overload it. If this occurred, the cone 12 would lower to return the primary Crusher ldd to proper operating eiliciency which would result in a larger sized material leaving the primary crusher. As this larger size will require more power to handle it in the secondary Crushers, it will be appreciated that a portion of the need for additional loading for the secondary Crushers may be supplied by a coarser material being fed to these crushers. The reverse operation is true, and when the feed stream to the primary crusher is reduced, the cone will raise to provide a liner grind which will require less power in passing through the secondary Crushers.

FIGURE 4 illustrates a further modiied form of this invention which is identical with that shown and explained in FIGURE 3, except that the overload devices 24 are not employed and the load on the crushers is sensed by determining the level of material in each crusher.

The primary Crusher indicated generally at e is provided at its inlet above the working surface on the cone 12a with a source of radiation 6i) which emits radiation across the feed inlet of the crusher. On the other side of the crusher a device indicated at 6l, such as a Geiger counter, senses the intensity of the radiation at this point. The sensing device 6l preferably senses radiation over a vertical distance of about one foot. As the material within the mouth of the Crusher will absorb radiation emitted by source t?, the amount of radiation received at device 61 will be dependent upon the level of material in the crusher.

Preferably, the sensing means 6l will be arranged so that with the material level in the Crusher at the bottom of the sensing means the output will be minus it) millivolts. As the level of material rises in the crusher the signal wih increase proportionally until the output with the level even with the top of device 61 will be zero miilivolts.

The signal emitted by device 61 will be amplified in amplilier A and fed to the pneumatic converter 62 wherein the signal is converted to a pneumatic signal. The pneumatic signal is fed to the controller recorder system 63 which controls the operation of valves 44 and 45 to effect movement of plunger 35 in the same manner as in the FlGURE 3 embodiment. Thus, as the level of material in the Crusher rises above the desired level the controller recorder system will lower the cone Zrz to increase the spacing between the cone lilla and the crusher ring lia, and thus reduce the load in the Crusher and 9 permit the level of material therein to decrease. Alternatively, the feed rate to primary crusher 149e could be varied in response to the level sensing device.

The secondary crushers Ulf and 16g are also provided with radiation sources 60 and radiation sensing means 61. The signal from the sensing means is amplified in amplier A and fed to pneumatic converter 62 in the same manner as in the primary crusher control system.

The signals from t'ne pneumatic converters associated with each secondary crusher govern the operation of the splitter for determining the relative amounts of material fed to the two secondary systems, as well as the speed of the conveyor i8 to determine the total amount of material fed to the system, in the same manner as in the FIGURE 3 embodiment of this invention.

It might be noted that where the crushing surfaces of the secondary crushers have been Worn to different extents, that the setting of the load ratio device 31 in the manner explained in FIGURE 3 will result in the level in one secondary crusher being maintained higher than the level in the other secondary crusher to thus increase the feed head on one crusher and maintain both secondary crushers operating at the desired eiiiciency.

From the above it Will be seen that systems have been provided for operating one, a portion, or all of a plurality of cone crushers at the desired efficiency. ln the FIG- URE l form of the invention, a single crusher is controlled to operate at desired efficiency. In the FIG- URE 2 form of the invention the secondary crushers operate at desired efciency. In the FIGURES 3 and 4 forms of the invention, all of the crushers operate at a desired efficiency.

As an alternative control system it is obvious that the load on the secondary crushers can be utilized to vary the height of piston 35, thus varying the size of material fed to the secondary crushers. In this system the means of controlling conveyor belt speed shown in FGURE l would be used.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as Well as in the details of the illustrated construction, may be made Within the scope of the appended claims without departing from the spirit of the invention.

What We claim is:

l. The method of operating a plurality of one-type crushers in which feed from a primary crusher is directed to a secondary crusher comprising, measuring the loading of each of the primary and secondary crushers, comparing the measured loading of the secondary crusher with a selected loading and varying the feed of material to the primary crusher in accordance with the comparison of the measured and selected loading to increase or decrease the feed to the system to maintain the secondary crusher operating at approximately a selected efficiency, comparing the loading of the primary crusher with a selected value and moving the ring and cone relative to each other in the primary crusher to maintain it operating at a selected efficiency.

2. The method of operating a plurality of cone-type crushers in which feed from a primary crusher is directed to a plurality of secondary crushers comprising, measuring the loading of each of the secondary crushers, comparing the measured values and directing more or less of the stream of material from the primary crusher to each of the several secondary crushers to maintain the loading f the several secondary crushers at selected relative values, comparing the loading of the several secondary crushers with a selected loading and varying the feed of material to the primary crusher in accordance with the comparison of the measured and selected loading to increase or decrease the feed to the system to maintain the secondary crushers operating at a selected efficiency, comparing the loading of the primary crusher with a selected value and moving the ring and cone relative to it? each other in the primary crusher to maintain the loading of the primary crusher at a selected eiciency.

3. The method of operating a plurality of cone-type crushers in which feed from a primary crusher is directed to a secondary crusher comprising measuring the loading of each of tne primary and secondary crushers, comparing the measured loading of the secondary crusher with a Vselected. loading and moving the ring and cone relative to each other in the primary crusher to maintain the secondary crusher operating at approximately a selected eciency, and comparing the loading of the primary Crusher with a selected loading and varying the feed of material to the primary crusher in accordance with the comparison of the measured and selected loading to increase or decrease the feed to the system to maintain the primary crusher operating at the selected eciency.

4. The method of operating a plurality of cone-type crushers in which feed from a primary crusher is directed -to a plurality of secondary crushers comprising measuring the loading of each of the secondary crushers, comparing the measured values and directing more or less of the stream of material from the primary crusher to each of the several secondary crushers to maintain the loading of the several secondary crushers at selected relative values, comparing the loading of the several secondary crushers with a selected loading and moving the ring and cone relative to each other in the primary crusher to maintain the several secondary crushers operating at approximately the selected eciencies, and comparing the loading of the primary crusher with a selected loading and varying the feed of material to the primary crusher in accordance with the comparison of the measured and selected loading to increase or decrease the feed to the system to maintain the primary crusher operating Iat the selected efficiency.

5. The method of operating a plurality of cone-type ore crushers in which feed from a primary crusher is directed to a plurality of secondary crushers comprising, measuring the load on each of the secondary ore crushers, comparing the measured values and directing more or less of the stream of ore from the primary ore crusher to each of the several secondary ore crushers to maintain the load on the several secondary ore crushers at selected relative levels.

6. The method of operating a plurality of cone-type ore crushers in which feed from a primary crusher is directed to a plurality of secondary crushers comprising, measuring the load on each of the secondary ore crushers, comparing the measured values and directing more or less of the stream of ore from the primary ore crusher to each of the several secondary ore crushers to maintain the load on the several secondary ore crushers at selected relative levels, comparing the measured load on the secondary ore crushers with a selected load, and varying the feed of ore to the primary ore crusher in accordance with the comparison of the measured and selected load to increase or decrease the ore `fed to the system by an amount needed to maintain the secondary ore crushers operating at a selected efficiency.

7. The method of operating a plurality of cone-type ore crushers in which ore is first crushed in a primary ore crusher and then fed into a plurality of secondary ore crushers comprising, measuring the load on each of the secondary ore crushers, comparing the measured loads With a selected load at which desired efficiency of operation of the secondary ore crushers would be obtained, and varying the height of the cone of the primary crusher in accordance with the compared average load and selected load to increase or decrease the size of ore fed to the secondary crusher as necessary to attain the desired eiliciency of operation of the secondary ore crushers.

8. The method of operating a plurality of cone-type ore crushers in which feed from a primary crusher is directed to a plurality of secondary crushers comprising, measuring the load on each of the secondary ore crushers, comparing the measured values and directing more or less of the stream of ore from the primary ore crusher to each of the several secondary ore crushers to maintain the load on the several secondary ore crushers at selected relative levels, comparing the load on the secondary ore crushers with a selected load value, and varying the height of the cone of the primary ore crusher in accordance with the comparison of said load on the secondary ore crushers and said selected load value to increase or decrease the ore size to the secondary crushers by an amount needed to maintain the secondary ore crushers operating at a selected eiliciency.

9. The method of operating a plurality of cone-type ore crushers in which ore is first crushed in a primary ore crusher and then fed into a plurality of secondary ore crushers comprising, measuring the load on each of the secondary ore crushers, comparing the load on the secondary ore crushers with a selected load value at which a desired eiciency of operation of the secondary ore crushers would be obtained and varying the rate of feed of ore to the primary ore crusher in accordance with the comparison to increase or decrease the Vamount of ore fed to the system as necessary to attain the desired efficiency of operation of the secondary ore crushers.

l0. An ore crushing system comprising, primary ore crusher means, means delivering feed ore to tne primary ore crusher means, a plurality of secondary ore crusher eans, motor means operating said ore crusher means, means receiving ore from the primary ore crusher means and dividing it into portions and delivering said portions to the respective secondary ore crusher means including movable means in the path of ore dow from the primary to secondary ore crushers, means for positioning said movable means, means sensing the load on each of said secondary ore crusher means, means for comparing the signals from the several sensing means and controlling said positioning means to vary the proportion of feed ore to the several secondary ore crusher means and maintain operation of all secondary ore crusher means at selected relative loads.

11. An ore crusher system comprising, primary ore crusher means, means delivering feed ore to the primary ore crusher means including means for varying the rate of delivery of feed ore, means for controlling said varying means, a plurality of secondary ore crusher means, motor means operating said ore crusher means, means receiving ore from the primary ore crusher means and dividing it into portions and delivering said portions to the respective secondary ore crusher means including movable means in the path of ore ow from the primary to secondary ore crusher means, means for positioning said movable means, means sensing the load on each of said secondary ore crusher means, means for comparing the signals from the several sensing means and controlling said positioning means to vary the proportion of feed ore to the several secondary ore crusher means and maintain operation of all secondary ore crusher means at selected relative loads, means receiving signals from each sensing means and signalling the total load to said means for controlling the varying means, said last mentioned controller means controlling said varying means in accordance with the signal received to increase or decrease the rate of delivery of ore to the primary ore crusher means upon a decrease or increase respectively in load on said secondary ore crusher means relative to a selected load to maintain operation of said secondary ore crusher means at selected loads.

12. An ore crusher system comprising, primary ore crusher means, means delivering feed ore to the primary ore crusher means including means for varying the rate of delivery of said ore, means for controlling said varying means, a plurality of secondary ore crusher means, motor means operating said ore crusher means, means receiving ore from the primary ore crusher means and dividing it into portions and delivering said portions to the respective secondary ore crusher means including movable means inthe path of ore iloW from the primary to secondary ore crusher means, means for positioning said movable means, means sensing the instantaneous load on each of said secondary ore crusher means, means for comparing tlie signals from the several sensing means and controlling said positioning means to vary the proportion of feed ore to the several secondary ore crusher means and maintaining operation of all secondary ore crusher means at selected relative loads, said means for controlling said varying means receiving signals from each of said sensing means and controlling said varying means in accordance with the signals received to increase or decrease the rate of delivery of ore to the primary ore crusher means upon a decrease or increase respectively in load on said secondary ore crusher means relative to a selected load to maintain said secondary ore crusher means operating at selected loads.

i3. An ore crushing system comprising, primary ore crusher means, means delivering ore to the primary ore crusher means including means for varying the rate of delivery of said ore, means for controlling said varying means, la plurality of secondary ore crusher means, motor means operating each ore crusher means, means receiving ore from the primary ore crusher means and dividing it into portions and delivering said portions to the respective secondary ore crusher means, means sensing the load on each secondary ore crusher means, said means for controlling receiving signals from each sensing means and controlling said varying means in accordance with the signals received to increase or decrease the rate of delivery of ore upon a decrease or increase, respectively, in load on said secondary crusher means relative to a selected load to maintain the right `amount of ore in the secondary ore crusher means for selected operating efciency thereof.

14. An ore crusher system comprising, primary ore crusher means, means delivering ore to the primary ore crusher means including means for varying the rate of delivery of said ore, means for controlling said varying means, said crusher including a ring and cone cooperable to crush ore, means for moving said ring and cone toward and away from each other, motor means for gyrating said cone, means operable in response to the load on said ore crusher means for operating said means for moving the ring and cone relative to each other to maintain the load on the ore crusher at selected value, secondary ore crusher means receiving ore from the primary ore crusher means and further reducing it in size, and means sensing the load on said secondary ore crusher means and signalling said means controlling said varying means in accordance with the load on said secondary ore crusher to increase or decrease the rate of delivery of ore to the primary ore crusher means upon a decrease or increase, respectively, in load on said secondary ore crusher means relative to a selected load.

l5. T'ne ore crusher system of claim 14 wherein the secondary ore crusher means is provided by a plurality of ore crushers, means is provided for receiving ore from the primary ore crusher means and dividing it into portions -and delivering said portions to the respective secondary ore crusher means including movable means in the path of ore ow from the primary to the secondary ore crusher means, means for positioning said movable means, means sensing the instantaneous load of each of the secondary ore crusher means, and means for comparing the signals :from the several sensing means and controlling said positioning means to vary the proportion of feed ore tothe several secondary ore crushers and maintain operation of the secondary ore crushers at selected relative loads.

16. An ore crushing system comprising, primary ore crusher means, said crusher means including a ring and cone cooperable to crush ore, means for moving said ring and cone toward and away from each other, motor means for gyrating said cone, secondary ore crusher means receiving ore from the primary ore crusher means and further reducing it in size, means sensing the load on said secondary ore Crusher means, and means receiving signals from said sensing means and operable in response to the signals received for operating said means for moving the ring `and cone relative to each other to maintain the load on the secondary ore Crusher means at a selected value.

17. An ore crushing system comprising, primary ore Crusher means, said Crusher means including a ring and cone cooperable to crush ore, means for moving said ring and cone toward and away from each other, motor means for gyrating said cone, secondary ore Crusher means receiving ore from the primary ore Crusher means and further reducing it in size, means sensing the load on said secondary ore Crusher means, means receiving signals from said sensing means `and operable in response to the signals received for operating said means -for moving the ring and cone relative to each other to maintain the load on the secondary ore crusher means at a selected value, means delivering ore to the primary ore Crusher means including means for varying the rate of delivery of said ore, means sensing the load on lthe primary ore crusher, and means operable in response to the load on said primary ore Crusher and controlling said varying means in accordance with the load on the primary ore crusher to maintain the load on the primary ore Crusher at a selected value.

18. A crushing system comprising a plurality of crushers, means for delivering feed material to the Crushers including means for dividing the feed into portions and delivering said portions to the respective Crushers, said dividing means including movable means in the path of the material tlow to the Crushers, means for positioning said movable means, means sensing the loading of each Crusher, means for comparing the signals from the several sensing means and controlling said positioning means to vary the proportion of feed material to the several crushers and maintain operation of lall the Crushers at selected relative loadings, and means -for controlling the rate of delivery of feed material to the Crushers in accordance with the load on said Crushers relative to a selected value yto maintain the Crushers operating at selected loading.

References Cited in the tile of this patent UNTED STATES PATENTS 2,024,424 Bryson Dec. 17, 1935 2,063,996 Gervais Dec. 15, 1936 2,172,317 Dickey Sept. 5, 1939 2,456,074 Newhouse Dec. 14, 1948 2,491,466 Adams Dec. 20, 1949 2,517,451 Sorteberg Aug. 1, 1950 2,727,694 Helmick Dec. 20, 1955 2,766,941 Weston Oct. 16, 1956 2,964,359 Abonnenc Dec. 13, 1960 OTHER REFERENCES Linke, German application S 34,878, Sept. 6, 1956. 

1. THE METHOD OF OPERATING A PLURALITY OF ONE-TYPE CRUSHERS IN WHICH FEED FROM A PRIMARY CRUSHER IS DIRECTED TO A SECONDARY CRUSHER COMPRISING, MEASURING THE LOADING OF EACH OF THE PRIMARY AND SECONDARY CRUSHERS, COMPARING THE MEASURED LOADING OF THE SECONDARY CRUSHER WITH A SELECTED LOADING AND VARYING THE FEED OF MATERIAL TO THE PRIMARY CRUSHER IN ACCORDANCE WITH THE COMPARISONOF THE MEASURED AND SELECTED LOADING TO INCREASE OR DECREASE THE FEED TO THE SYSTEM TO MAINTAIN THE SECONDARY CRUSHER OPERATING AT APPROXIMATELY A SELECTED EFFICIENCY, COMPARING THE LOADING OF THE PRIMARY CRUSHER WITH A SELECTED VALUE AND MOVING THE RING AND CONE REALTIVE TO EACH OTHER IN THE PRIMARY CRUSHER TO MAINTAIN IT OPERATING AT A SELECTED EFFICIENCY. 